The invention relates to a compressed-air disk brake and more specifically electropenumatic compressed air disk brakes.
A compressed-air disk brake is known from German Patent Document DE 40 32 885 A1. The disk brake for utility vehicles shown in that document has had good results per se, but a structural and constructional simplification is desirable for reducing its manufacturing costs. The same applies to the brake systems disclosed in German Patent Documents DE 16 55 103 B2 and DE-OS 16 55 854.
Compressed-air cylinders in different embodiments are known, for example, from "Bosch Automotive Engineering Manual", 22nd Edition, ISBN 3-18-419122-2. On Page 655, this manual mentions piston-type as well as diaphragm-type cylinders as well as combined single-chamber spring-loaded cylinders as successful standard examples.
The above-mentioned cylinders have had good results per se and represent a component of the overall brake system which is reliable as a whole. Based on this starting situation, the invention uses the idea that the interaction of individual components of the disk brake or of the whole brake system, particularly of the cylinders, in modern, electronically controlled brake systems (EBS brake systems) be rethought and optimized.
The invention achieves this goal. The disk brake according to the invention thus differs from the disk brake of the above-mentioned type in that, in each case, at least one control module with electronic and pneumatic/mechanical components (particularly a complete EBS wheel module) is integrated in the brake and/or in the brake cylinder. In addition, the invention achieves this goal in that, in the case of a brake cylinder of the above-mentioned type, it arranges a control module directly on one of the housing sections of the brake cylinder.
The invention implements an advantageous and low-cost integration of a control module with the actual disk brake, particularly with its brake cylinder, and therefore combines previously separate components (brake cylinder or other elements of the disk brake with the control module) to form a constructional unit.
When implementing modern electronic braking systems, the desire to obtain intelligent vehicle brakes has intensified in recent times, which vehicle brakes would integrate all electronic and mechanical control elements in the wheel brake (or arrange these elements in the brake). Among other things, this would considerably reduce the mounting expenditures in the vehicle.
The idea of a wheel-related control module has developed therefrom which combines electronic and pneumatic components with one another. Such a module is, for example, designed such that a compressed-air pipe as well as an electronic control cable lead to the module; in which case, by means of the pneumatic and electronic components of the control module, at least the functions "control pressure into the brake cylinder" and "lower pressure" can be implemented. For this purpose, the control module comprises, for example, a relay valve, preferably several solenoids connected in front of the relay valve, a pressure sensor, a bus connection, a compressed-air connection, etc. Preferably, the control modules of different wheels should be able to communicate with one another, either by way of a control unit or directly.
If, according to the invention, the control module is now combined with the disk brake and/or the brake cylinder to form a constructional unit, the mounting and cabling expenditures are reduced because, instead of several separate elements, only one component must be integrated and inserted in the installation space of the wheel brake.
A particularly preferred embodiment of the invention is that the brake cylinder and the disk brake form a construction unit. This embodiment of the invention further considerably simplifies the construction of the disk brake (specifically also if the control module is not also integrated in the disk brake). The integration of the control module first causes the elimination of otherwise required electric and pneumatic connection lines and of an additional housing. The additional integration of the brake cylinder in the brake construction then has the additional result that an otherwise required connection is eliminated between the brake cylinder and disk brake components which, during repair and assembly work, also always represents an additional possible source of errors.
According to a particularly preferred and expedient embodiment of the invention, the brake cylinder is integrated in the caliper. As a result, no more dirt can penetrate into the caliper when the brake cylinder is exchanged. On the contrary, it will only be necessary, for exchanging the brake cylinder, to exchange an insert which comprises the internal components of the brake cylinder (piston, piston rod, etc.). An additional sealing is eliminated and it is possible to expose the whole brake interior only to dried compressed air from the brake system, which, among other things, also reduces the danger of corrosion. This will be explained in greater detail.
The invention also makes it possible to provide a standardized brake cylinder which no longer has to be adapted to different usages. This applies particularly when the control module is designed such that a complete EBS function can be implemented by it. In this context, it is particularly advantageous for the adjusting of the otherwise pneumatically operated brake to take place by an electric adjusting motor. By the electric adjusting motor and a suitable control software, it is also possible to design the adjusting mechanism at particularly low cost. As the result of the construction of the cylinder as a piston cylinder, a particularly compact construction can be achieved.
According to another, particularly preferred embodiment of the invention, the control module is molded directly to the housing section for the ventilation chamber. The control module is therefore arranged in an advantageous and simple manner in a component of the brake which must be changed only insignificantly in order to integrate the control module in it or combine it with this component. In addition, this variant of the invention has the special advantage that the control module is mounted directly and without the requirement of additional internal or external feed lines on the part of the brake cylinder which has a direct access to the ventilation chamber of the cylinder. It is therefore possible to control the air for acting upon the piston(s) directly behind the piston. Another advantage is that the additional components, for example, in the case of an arrangement of the control module on the housing, the other components, such as the cover, the piston and the diaphragm--do not have to be changed further in order to equip the brake cylinder, in contrast to the conventional construction, with a control module. Another advantage of this embodiment of the invention is that the flanging onto the brake--preferably the flanging to a compressed-air disk brake for trucks--because of the integrated module, requires no adaptation. Another significant advantage of the invention is that, by means of it, it is generally possible to retrofit in an uncomplicated and easy manner a vehicle series of a conventional brake system, to form an EBS brake system. Modifications of the control module can be carried out without additional expenditures; only the housing may have to be adapted in a simple manner. Another advantage is finally, that the cover of the compressed-air cylinder is normally the component of the utility vehicle brake which is the easiest to change (type of construction).
Additional advantageous embodiments of the invention are found in the other subclaims.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.